Impact of clinate change on soil

1. Impact of climate change on
soil physical properties

2. List of soil physical properties
 Soil Texture
 Soil Structure
 Density of Soil
 Pore Space
 Soil permeability
 Soil Consistence
 Soil Colour
 Soil Temperature
 Soil moisture

3. Introduction
 Soil physical properties define movement of air and
water/dissolved chemicals through soil as well as
conditions affecting germination, root growth and erosion
processes.
 Soil physical properties form the foundation of several
chemical and biological processes, which may be further
governed by climate, landscape position and land use.
 Thus, a range of soil physical properties when altered by
climate change can trigger a chain reaction that leads to
soil environment, which may greatly influence growth and
production of crops.

4. Background Info
 The intergovernmental panel on climate change
has projected that in 21st century South Asia is
going to be hit hard by climate change.
 Changes in mean annual temperature will exceed
2⁰C above the late 20th century baseline and there
can be declines in the absolute amount of
precipitation during December to February.

5. Cont….
 Temperature, precipitation and enhanced CO2
level in the atmosphere, the three climate change
can affect crop yield directly or indirectly through
changes in properties and processes in soil.
 Studies pertaining to the effects of climate change
on soil processes and properties are now becoming
available and it is becoming clear that climate
change will impact soil organic matter, soil water,
soil temperature.

6. Various effects
Porosity and pore size distribution:-
 Porosity and pore size distribution are a measure of the
ability of a soil to store root zone water and air necessary
for plant growth
 Soil porosity and water release characteristics directly
influence a range of soil physical indices including soil
aeration capacity, plant available water capacity and
relative field capacity.
 Now future climate change scenarios consisting of
elevated CO2 and temperature and variable and extreme
rainfall events may alter soil porosity and pore size
distribution.

7. Soil Structure:-
 The structure of soil dictates organic C
accumulation, infiltration capacity, movement and
storage of gases, water and nutrients, emergence
of crops and roots.
 Since nature and quality of the structure of a
particular soil are strongly influenced by the
amount and quality of O.M present, a decline in
soil O.M level as could occur under climate
change may lead to a decrease in soil aggregate
stability, increase in susceptibility to compaction.

8. Cont…
 Soil with high clay contents have potential to
shrink when dry, resulting in formation of large
cracks.
 Due to climate change there is possibility of
drought, means drier climatic conditions would be
expected to increase the frequency and size of
crack formation.
 The increase drying condition of soil due to
climate change will lead to increased difficulties
in the management of clayey agricultural soils
with a high shrink swell potential.

9. Infiltration rate:-
 Soil infiltration rate is gaining increasing
importance in soil water modeling but it can
significantly change with soil use, management
and time.
 The soil available water may respond rapidly to
climate change, especially to variable and high
intensity rainfall and drought events.
 Enhancing water infiltration in soil may help in
migrating the impacts of severe rainfall and
drought events.

10. Bulk Density:-
 Bulk density is another routinely assessed soil
property in agricultural systems used for
characterizing the state of soil compactness,
aeration and infiltration.
 Since bulk density generally negatively
correalated with soil organic matter, loss of
organic C from increased decomposition due to
elevated temperatures may lead to increase in bulk
density and hence making soil more prone to
compaction.

11. Soil Temperature:-
 There is close relationship between air temperature and
soil temperature and general increase in air temperature
will inevitably lead to an increase in soil temperature.
 As with soil moisture, soil temperature is prime mover of
in most soil processes. Warmer soil temperature will
accelerate soil processes, rapid decomposition of organic
matter, increases microbiological activity and chemical
weathering of minerals.
 Increased temperature is likely to have a negative effect on
C allocation to the soil, leading to reductions in soil
organic C and creating a positive-feedback in the global C
cycle (increased temperatures lead to increased CO2
release from soils to the atmosphere, which leads to more
increases in temperature).

12. Soil Moisture:-
 Soil water can be fluctuated by a number through
climate change such as precipitation causing rapid
changes in soil water since the time scale for
response is usually within a few hours.
 Temperature increase resulting in greater evapo-
transpiration loss of water from soil.
 Thus, plant canopy suffers from limited water
supply due to climate change or soil induced
drought.

13. Climate change adaption measures related to
agricultural soils:-
 Use plant to grow soil carbon
 Use micro-organisams to convert soil carbon in stable
forms
 Reduce herbicide, pesticides and fungicides
 Use correct tillage methods
 Control weed without soil damage
 Avoid erosion
 Avoid farming techniques that destroy soil carbon
 Reduce nitrogen applications

14. Conclusion
 The quantitative evaluation of predicted climate change effect
on soil physical properties is a difficult task due to
uncertainties in weather forecast.
 Land degradation issues are closely related with adverse effects
of climate change. The conservation farming has shown
positive results in minimizing land degradation.
 In adoption of conservation tillage and residue management, it
is essential that complete package of practices may be
identified based on intensive research for each agro ecological
region.
 However, the site specific management practices for soil and
water conservation, crop improvement and integrated nutrient
management needs to be identified to overcome impact of
climate change on physical properties of soil.